1. Field of the Invention
The invention relates to a method and device for producing nuclear images by means of a radiation detector. In particular, the invention relates to a method and device for producing nuclear images by means of a scintillation gamma camera.
2. Description of the Prior Art
Scintillation cameras are widely used for producing nuclear images of a patient under examination. Of particular interest are whole-body images of the patient. Whole-body imaging is performed either by a linear scanning movement of the scintillation gamma camera along a patient table, or by a linear scanning movement of the patient tably whereby the camera is kept stationary, or a mixture of both movements. Scanning is performed in one or more passes along a scan axis. For data acquisition and imaging a mask field of view is produced by masking the camera's field of view either electronically or mechanically.
The possibility of mechanically masking is for example illustrated in U.S. Pat. No. 4,012,636 (Engdahl et al.)
The U.S. Pat. No. 3,970,852 (Richey et al.) and the European Patent Application 0,047,177 (Inbar) describe examples for electronically masking.
In all three cases the mask field of view lies within the boundaries of the (circular) camera's field of view.
The European Patent Application 0,047,177 also describes a method and circuit for correcting non-uniform scanning time interval distribution generated by a mask field of view along an axis perpendicular to the scan axis. However, the correction factors are predetermined in off-line measurements in accordance with the activity distribution of a known reference radiation field.